Proposed International Space Station Life Support Hardware Changes for a Lunar/Mars Surface Human Habitat � Common Cabin Air Assembly Case Study

The International Space Station (ISS) was designed to be a microgravity space station in Earth orbit. As such, many design features of the ISS Environmental Controls and Life Support Systems (ECLSS) were included specifically to facilitate microgravity operation of the many fluid systems. These features were usually complicated, costly and/or inconvenient in ways that made operation, maintenance and/or in-situ repair more difficult than for Earth-based systems. As a reference point for future lunar/Mars surface habitat ECLSS system designers, changes to the ISS ECLSS can be envisioned to take advantage of lunar/Mars gravity environments while also reducing complexity, mass, volume and cost. This paper will review the ISS Temperature and Humidity Control (THC) system Common Cabin Air Assembly (CCAA) as a case study and provide the author�s proposed changes to facilitate more optimized gravity designs and system operation. Where appropriate, reliability and maintainability improvements based on ISS operational experience and possible 3D printing options will be included.